1. Field Of The Invention
The present invention relates generally to cementing heads for introducing cement along with cement plugs into an oil or gas well, and particularly to a cementing head adapted for use in situations where there is not sufficient room to use typical cement plug containers.
2. Description of the Prior Art
In the cementing of casing into the bore hole of an oil well, it is very common to use cement plugs which are placed at the beginning and/or end of the slug of cement that is pumped into the well. The purpose of the cement plugs is to wipe the walls of the casing and also to provide a distinct boundary between the cement and other fluids which are in front of or behind the cement.
Very typically when such cement plugs are being utilized, the plugs will initially be placed in a plug container which is mounted on top of the upper end of the well casing which extends out of the ground. The plugs are contained in the plug container along with release mechanisms which allow the plugs to be dropped into the casing at the appropriate time. These plug containers are often referred to by the more general terms cementing head or cement head.
Typical examples of such prior art plug containers are seen in U.S. Pat. No. 4,613,161 to Brisco, U.S. Pat. No. 3,863,716 to Streich, U.S. Pat. No. 2,620,037 to McClendon, U.S. Pat. No. 4,290,482 to Brisco, and U.S. Pat. No. 3,322,197 to Baker et al., all assigned to the assignee of the present invention.
With all of these prior art devices, the cementing plugs are actually contained in the plug container which sits on top of the upper end of the well casing.
One difficulty which is sometimes encountered is that at some drilling sites, the equipment being utilized does not provide sufficient clearance above the upper end of the well casing for the mounting of these standard cement plug containers.